Inside casing cutter



I E. H LEACH INSIDE CASING CUTTER Dec. 1, 1936.

Filed April 20, 1936 ATTORNEYS Patented Dec. 1, 1936 UNITED STATESPATENT OFFlCE INSIDE CASING CUTTER Elton lLLeach, Lake Charles, La.Application April 20, 1936, SerialNo. 75,444 5 Claims. (Cl. 81 1 94)This invention relates to pipe cutters adapted to be used for cuttingoff a section of piping in a well.

An object of the invention is to provide novel cam means for actuatingthe cutters.

A further object is to provide a novel means for automatically releasingthe cutting means after the cutting operation has been completed.

A further object is to provide a device of this character which will beformed of a few strong simple and durable parts, which will beinexpensive to manufacture and which will not easily get out of order.

With the above and other objects in view the invention consists ofcertain novel details of construction and combinations of partshereinafter fully described and claimed, it being understood thatvarious modifications may be resorted to within the scope of theappended claims without departing from the spirit or sacrificing any ofthe advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 shows in longitudinal section, a device constructed inaccordance with the invention, parts being shown in elevation.

Figure 2 is a cross sectional view taken on the line 2-2 of Figure 1looking in the direction of the arrowheads.

Figure 3 is a cross sectional view taken on the line 33 of Figure 1looking in the direction of the arrowheads.

Figure 4 is a cross sectional view taken on the line 44 of Figure 1looking in the direction of the arrowheads.

Referring now to the drawing on which like characters of referencedesignate similar parts in the various views, l0 designates a tubularbody having a screw thread connection I l at the upper end with thedrill pipe l2, rotation of whichrotates the tubular body in its axis.The tubular body is provided at the lower end with a guide point l3 forcentering the tool in the well casing to be cut, and the body isprovided on the sides with tension blocks M which are urged radially bysprings l5 behind them to engage the inner face of the well casing andcoact with the point l3 in centering the tool in the well.

A cylindrical cam plate I6 is rotatably mounted in the lower end of thetubular body and is provided with an extension I! which is received in arecess l8 formed in a plug I9 which closes the open bottom of thetubular body and forms means for permitting assembly of the cam platewith the tubular body and also forms means for securing the guide pointto the tubular body. The cam plate is provided in the top face withpreferably three spiral slots 20, best shown in Figure 4, the inner endsof which are disposed near the axis of the cam plate and the outer endsof which open through the cylindrical wall of the cam plate. The camplate is provided with an axialopening provided with a spiral groove 2|to receive the spirally threaded end 22 of a stem 23; the lower end ofwhich enters a socket 24 formed in the plug l9. I

Preferably three cutters 25, best shown in Figure 3, are slidably fittedin radial openings 26 formed in the tubular body l0 and each cutter isprovided on the underneath face with a pin 21 which enters an associatedspiral slot 20 on the cam plate '5. When the stem 23 is moved verticallythe plate I6 will be rotated and the pins 21 will be movedlongitudinally in the spiral slots 20 pulse of a helical spring 28,withdraws the cutters to initial position.

The stem 23 is provided with a stop collar 29 and the helical spring 28is confined under tension between this stop collar and an abutment 30projecting inwardly from the bore of the tubular body. When the stem 23is manually pulled upwardly to move the cutters outwardly, the springwill be compressed between the stop collar and the abutment and willimmediately expand and withdrawthe cutters when the stem 23 isuncoupledfrom its pulling means. A key 3| is secured in the abutment 3|] by meansof a screw 32 and projects into a longitudinal key-way 33 formed in thestem 23. Thus the stem is confined against rotation on its axis but maybe readily moved vertically on .the key to cause the threaded end 22 ofthe stem to rotate the cam plate clockwise and move the cuttersoutwardly and rotate the cam plate counter-clockwise to withdraw-thecutters. 7

Referring now to Figure 1, it will be seen that a pair of latches 34 arepivoted intermediate their ends on pivot pins 35 disposed in a kerf 36formed in the upper end of the stem 23. The lower ends of the latchesare cut away obliquely to receive between them a helical spring stantlytends to urge the lower ends outwardly and consequently hold the upperends of the latches inwardly. The upper ends of the latches are providedwith hooks 38 which in normal position enter a circumferential recess 39formed at the lower end of a stem 40, the stem being headed up as shownat 4| below the recess to provide an abutment against which the hooksbear when the stem 40 is manually pulled upward to raise the stem 23 andmove the cutters 25 outwardly to operative position. A cable 42 isattached to the upper end of the stem 40, and like the drill pipe I 2 isof sufiicient length to reach to the top of the well so that both stems40 and 23 may be pulled upwardly as a unit while the drill pipe I2 isbeing rotated to simultaneously move the cutters outwardly and advancethe same through a circular path to sever the pipe section in the well.

Referring now to Figure 1, it will be seen that a collar 43 is securedin the bore of the tubular body by screws 9 passed through the tubularbody In above the lower ends of the latches. The collar is provided witha circular cam face 44 which is flared downwardly from about the centerof the collar to the lower end of the collar. The lower ends of thelatches are provided with cam projections 45 which, when the stem 23 ispulled upwardly, first engage the wide lower endof the cam wall 44 andride upwardly on the wall to the narrow upper end, during which progressthe hooks 38 of the latches will be gradually moved outwardly from therecesses 39 to disengage from the head 4| of the stem 40 and release thestem 40 so that it is uncoupled from the stem 23 at the time the cutters25 reach their outermost limit of movement in performing the inside outon the well casing. Immediately the stem 40 is uncoupled, as justdescribed, the spring 28 expands and. moves the stem 23 downwardly tosimultaneously withdraw the cutters 25 and lower the latches 34, thespring 31 of the latter moving the lower ends of the latches outwardlyduring such lowering movement and returning the hooks 39 to'position toagain receive the stem 40 for a subsequent cutting operation.

The stem 40 is preferably formed on two interfitting parts asillustrated in Figure 1, connected by a frangible shear pin- 46. In caseof emer gency where any of the parts of the tool become jammed, a quickjerk of the cable will break the shear pin and permit'the cable to beremoved from the drill pipe l2.

Since the operation of the device has been described as the descriptionof the parts progressed, it is thought that the invention will be fullyunderstood without further explanation.

What is claimed is:

1. A cutter for oil well tubing and the like comprising a rotatabletubular body, vertically movable aligned stems in the body, a head onone of the stems, spring pressed latches pivoted on the other stem andhooked over said head to couple the stems together, a projection in thebody adapted to dislodge the latches from the head to uncouple the stemsat a predetermined point in the upward movement of the stems, a rotarycam plate in the body having spiral grooves, radially movable cutterscarried by the body and having projections fitting in said grooves, oneof the stems having a spiral thread, there being a spirally threadedaxial opening in the cam plate receiving the thread of said stem, and aspring on the last named stem compressed by upward movement of the stemsand adapted to return the lower stem, the cam plate and the cutters toreleased position upon uncoupling of the stems from each other.

2. A cutter for oil well tubing and the like comprising a rotatabletubular body, vertically movable aligned stems in the body detachablyconnected together, means for disconnecting the stems from each other ata predetermined point in the upward movement of the stems, a rotary camplate coaxial with the body and having spiral grooves in the top face,radially movable cutters carried by the body and having projectionsfitting in said grooves, one of the stems having a spiral threadthereon, said cam plate having a spirally threaded opening receiving thethread of said stem, a key on the body engaging the last named stem forpreventing rotation of the stem, and a spring on the last named stemcompressed by upward movement of the stem to return the stem, the camplate and the cutters to initial position upon the stems beingdisconnected from each other.

3. A cutter for oil well tubing and the like comprising a rotatabletubular body, a cable extending axially in the body, aligned upper andlower stems inthe body, the upper stem being connected to the cable andhaving a groove in the lower end, a pair of spring pressed oppositelydisposed pivoted latches on the upper end of the lower stem havingtheirupper ends normally engaged in said groove to couple the stemstogether, a collar in the bore of the tubular body having a cam faceflaring downwardly and outwardly, cam projections on said latchesadapted to engage said cam face whereby to move the latches against thetension of their controlling spring and dislodge the latches from saidgroove to uncouple the stems, radially movable cutters in the tubularbody, a' cam member connected with said cutters for 'moving the cuttersoutwardly and inwardly, the cam member having an axial screw threadedopening, screw threads on the lower stem engaging said threaded opening,and a spring assembled with the lower stem adapted to be compressed uponupward movement of the stem for returning the stem, the cam plate andthe cutters to initial position upon uncoupling of the stems from eachother.

4. A cutter for oil well tubing. and the like comprising a rotatabletubular body; vertically movable aligned stems in the body, means forpulling the stems as a unit upwardly in the body, a head on one of thestems, spring pressed latches pivoted on the other stem and hooked oversaid head to couple the stems together, a projection in the a bodyadapted to dislodge the latches from the head to uncouple the stems at apredetermined point in the upward movement'of the stems, radiallydisposed cutters carried by the tubular body, and means operativelyconnected to the cutters and to the lowermost one of the aligned stemsfor actuating the cutters.

5. A cutter for oil well tubing and the like comprising a rotatabletubular body, vertically movable aligned stems in the body, means forpulling the stems upwardly in the body, a head on the upper stem, springpressed latches pivotedon the lower stemand hooked over said head tocouple'the stems together, a projection in the body, adapted to dislodgethe latches from the head to uncouple the latches at a predeterminedpoint in'the upward movement of the stems, radially disposed cutterscarried by the tubular body, means operatively connected to the cuttersand to the lower stem for moving the cutters outwardly when the stemsare raised, and a spring cooperating with said last mentioned meansforretracting the cutters after said stems have been uncoupled.

ELTON H. LEACH.

